Nerve Structure:

Nerves are like telephone cables. They are surrounded by a tube or sheath and have multiple fine nerve fibres running down the centre.

 

           

 

Nerve Injuries:

1. Stretch
2. Crush – acute or chronic
3. Cut – partial or complete

                

 

 

When a nerve is cut the nerve fibres beyond the cut will die but the sheath usually survives.

If the cut is only partial the adjacent nerve may be bruised but often recovers fairly quickly.

Nerves regenerate at a rate of 1mm / day + 2 – 4 weeks to get started.

 

Some of the regenerating nerve fibres may escape from the nerve sheath and cause a painful neuroma.

If a nerve is accurately repaired using sutures finer than hair under a microscope then the nerve will gradually recover. The nerve may be irritable or painful during recovery. The progress of nerve recovery can be determined by tapping the nerve gently. The area of maximum sensitivity should gradually move along the line of the nerve.

             

 

Neuroma:

     

 

If the nerve is not repaired the raw nerve fibres escape from the protective sheath and form a mass of raw nerve endings.

This is called a neuroma and is often very painful when taped.

It is important to note that in this circumstance pain does not equate to damage to the tissues.

Pain in general is a useful and protective function for the body. Pain tells us when we have our hand on the hot plate to “get it off” or risk burning the hand. Ie it is a protective mechanism to prevent damage to the body.

The pain from a neuroma does not equate to damage. It is not a useful function. It tends to discourage us from using the area but this is the worst thing we can do. It is vital to keep using the injured part even though this causes us pain.

 

Treatment of Nerve Injuries:

1. Nerve repair using a microscope

2. Nerve grafting - nerve from another part of the body eg side foot
- artificial nerve tube

3. Hand therapy
- encouragement to use the hand
- scar massage
- desensitization - tapping fingers
- exposure to different textures eg rub against towel
Note it is normal to experience pain during this treatment. Many people describe a feeling of nausea due to the pain but this usually passes.
- silicone gel eg Cica Care, Opsite

4. Pain management
- pain clinic
- medications   eg Lyrica,  Gabapentin,  Endep
- local anaesthetic creams

Problems of nerve injuries

1. Neuromas

2. Variable recovery of motor or sensory function

3. Pain syndromes eg “Complex Regional Pain Syndrome”

 

 

LAST UPDATED ON MONDAY, 08 SEPTEMBER 2008 19:30